This invention relates to newly identified polynucleotides, polypeptides encoded by such polynucleotides, the use of such polynucleotides and polypeptides, as well as the production of such polynucleotides and polypeptides. More particularly, the polypeptides of the present invention are interleukin-1 xcex2 converting enzyme like apoptosis protease-3 and interleukin-1 xcex2 converting enzyme like apoptosis protease-4, sometimes hereinafter referred to collectively as xe2x80x9cICE-LAP-3 and 4xe2x80x9d. The invention also relates to inhibiting the action of such polypeptides.
It has recently been discovered that an interleukin-1xcex2 converting enzyme (ICE) is responsible for cleaving pro-IL-1xcex2 into mature and active IL-1xcex2 and is also responsible for programmed cell death (or apoptosis), which is a process through which organisms get rid of unwanted cells. The present invention is directed to ICE-LAP-3 and 4 which are structurally related to ICE.
In the nematode caenorhabditis elegans, a genetic pathway of programmed cell death has been identified (Ellis, R. E., et al. Annu. Rev. Cell Biol., 7:663-698 (1991)). Two genes, ced-3 and ced-4, are essential for cells to undergo programmed cell death in C. elegans (Ellis, H. M., and Horvitz, H. R., Cell, 44:817-829 (1986)). Recessive mutations that eliminate the function of these two genes prevent normal programmed cell death during the development of C. elegans. The known vertebrate counterpart to ced-3 protein is ICE. The overall amino acid identity between ced-3 and ICE is 28%, with a region of 115 amino acids (residues 246-360 of ced-3 and 164-278 of ICE) that shows the highest identity (43%). This region contains a conserved pentapeptide, QACRG (residues 356-360 of ced-3), which contains a cysteine known to be essential for ICE function. The ICE-LAP-3 and 4 polypeptides of the present invention also have the same conserved pentapeptide and the cysteine residue which is essential for ICE function.
The similarity between ced-3 and ICE suggests not only that ced-3 might function as a cysteine protease but also that ICE might act as a vertebrate programmed cell death gene. ced-3 and the vertebrate counterpart, ICE, control programmed cell death during embryonic development, (Gagliarnini, V. et al., Science, 263:826:828 (1994).
ICE mRNA has been detected in a variety of tissues, including peripheral blood monocytes, peripheral blood lymphocytes, peripheral blood neutrophils, resting and activated peripheral blood T lymphocytes, placenta, the B lymphoblastoid line CB23, and monocytic leukemia cell line THP-1 cells (Cerretti, D. P., et al., Science, 256:97-100 (1992)), suggesting that ICE may have an additional substrate in addition to pro-IL-1xcex2. The substrate that ICE acts upon to cause cell death is presently unknown. One possibility is that it may be a vertebrate homolog of the C. elegans cell death gene ced-4. Alternatively, ICE might directly cause cell death by proteolytically cleaving proteins that are essential for cell viability.
The mammalian gene bcl-2, has been found to protect immune cells called lymphocytes from cell suicide. Also, crmA, a cow pox virus gene protein product inhibits ICE""s protein splitting activity.
The polypeptides of the present invention have been putatively identified as ICE-LAP-3 and 4. This identification has been made as a result of amino acid sequence homology.
In accordance with one aspect of the present invention, there are provided novel mature polypeptides which are ICE-LAP-3 and 4, as well as fragments, analogs and derivatives thereof. The polypeptides of the present invention are of human origin.
In accordance with another aspect of the present invention, there are provided polynucleotides (DNA or RNA) which encode such polypeptides.
In accordance with yet a further aspect of the present invention, there is provided a process for producing such polypeptides by recombinant techniques.
In accordance with yet a further aspect of the present invention, there is provided a process for utilizing such polypeptides, or polynucleotides encoding such polypeptides for therapeutic purposes, for example, as an antiviral agent, an anti-tumor agent and to control embryonic development and tissue homeostasis.
In accordance with yet a further aspect of the present invention, there is provided an antibody against such polypeptides.
In accordance with yet another aspect of the present invention, there are provided antagonists to such polypeptides, which may be used to inhibit the action of such polypeptides, for example, in the treatment of Alzheimer""s disease, Parkinson""s disease, rheumatoid arthritis, septic shock and head injuries.
These and other aspects of the present invention should be apparent to those skilled in the art from the teachings herein.